Dexter and other characters or things from Dexter's Laboratory have appeared in media besides itself. Outside media has featured many cameos and references to Dexter's Laboratory.
The Powerpuff Girls
- In the episode "Powerpuff Bluff", Dexter was seen sleeping with the other kindergarteners at Pokey Oaks Kindergarten.
- In the episode "Criss Cross Crisis", when Professor Utonium was switching everybody's bodies, one of them had Ms. Bellum switched with Dexter.
- In the episode "Ploys R Us", when Professor Utonium was taking toys from the toy store, there were plush dolls of Dexter, Dee Dee, and Monkey.
- In the episode "Imaginary Fiend", Koosy made a cameo as one of Bubbles' imaginary friends. Everyone kept responding with "Nobody likes that Koos jerk."
- In the episode "Forced Kin", Dexter was one of the people standing on the sidewalk.
- In the episode "Members Only", The Justice Friends all gathered up in a superhero meeting. This included Major Glory, Valhallen, Living Bullet, White Tiger, Tiki Torch, Rasslor, and Comrade Red. Krunk, despite being mentioned by Buttercup, does not make a cameo.
- In the episode "Toast of the Town", The Mayor was in Professor Utonium's lab and he went up to a button and said "Oooh! What does this button do?" This was a reference to Dee Dee.
- In the episode "Prime Mates", Mojo Jojo was sleeping with a Monkey doll.
The Grim Adventures of Billy and Mandy
- In the episode "The Grim Adventures of the Kids Next Door", When the Delightful Reaper was getting destroyed, kids from other Cartoon Network shows were flying out of it. Dexter, Dee Dee, and Mandark were three of them. Also, in the ending credits, one of the crossover parodies was a crossover between Dexter's Laboratory and My Gym Partner's a Monkey. It was called "My Gym Partner's a Mandark" and it had Mandark swinging on Jake's tail.
MAD
- In the episode "Once Upon a Toon", one of the original Cartoon Network characters was Dexter. Also, Dee Dee was seen as the one who got rid of all the old Cartoon Network shows.
My Little Pony: Friendship Is Magic
- In the episode "A Friend in Deed", Pinkie's line "Ooh, what does this bauble do?" was a reference to Dee Dee.
Robotboy
- In the episode ''Human Fist On Ice'' Dexter made a brief cameo in the arena as one of the guests in the audience.